Exploring the potential of UAV imagery for variable rate spraying in cotton defoliation application

Defoliants spraying is necessary to facilitate mechanized cotton harvesting.  However, traditional uniform spraying usually decreases the defoliation effects and increases the costs.  In order to address this problem, a variable rate spraying strategy was designed in the context of cotton defoliation.  UAV multispectral imagery was collected in a cotton filed ofYellowRiver BasininChina, and the imagery was mosaicked into an ortho-photo.  The indexes of NDVI and GNDVI were calculated, and the index maps were generated and later transformed into grid maps.  A plant protection UAV was used for variable rate spraying, with the chemical dose proposed by the grid maps.  Ground investigation before and after the spraying were conducted carefully to verify the defoliation effects.  Investigation results showed that the proposed variable rate spraying strategy yielded satisfactory results with less defoliants, which demonstrated that this technology has potential in the cotton defoliation applications. Keywords: multispectral remote sensing, cotton, defoliation, UAV DOI:  10.33440/j.ijpaa.20190201.0018   Citation: Yi L L, Lan Y B, Kong H, Kong F X, Huang H S, Han X.  Exploring the potential of UAV imagery for variable rate spraying in cotton defoliation application.  Int J Precis Agric Aviat, 2019; 2(1): 42–45.